I have used flexi-fans in the past and while they pull lots of air at low speed they don't pull enough at around 2800 which is where I pull the engine. Plus, I have to flatten the pitch to clear the harmonic balancer and the A/C compressor pully. One of those I bought on the road was a reverse pitch and was mis-boxed. I didn't notice it, which created quite an adventure until I got back to the FLAPS to exchange it.

1951 3800 1-ton
"Earning its keep from the get-go"
In the DITY Gallery
1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.